Conventional coffee mugs tend to dissipate heat rapidly, and the slow drinker ends up swallowing a large amount of lukewarm or cold beverage. The problem has been somewhat palliated by the introduction of plastic thermo-insulated cups. But since most of the heat is dissipated through the top opening of the vessel, the insulation of the walls and bottom is only partially effective.
People such as drivers, fishermen, railroad engineers, heavy equipment and crane operators, who like to sip hot or cold beverages in a moving vehicle find conventional drinking cups awkward to use in such situations, and subject to spillage.
People working in a dusty environment such as on construction sites, textile mills, steel mills, etc., who like to drink hot or cold beverages at work, need a drinking cup which will protect its contents from the ambient dust.
Cups, mugs or tumblers with removable covers have been provided in the past, but they are often impractical, awkward to use and unsightly.
Tumblers, partially covered on top, have been available as training cups for infants. They are very awkward to use, and do not resolve the problem of spilling when such a cup is knocked over by a clumsy child.
There is also a need for a dispenser for spices, sugar, flour or other cooking ingredients, which can be held and opened single handedly while the other hand is busy stirring or performing other cooking chores.